This invention relates to an acoustic resonator and a method of making said resonator. More particularly, this invention relates to a method of making said resonator wherein all processing steps are accomplished from a single side of its supporting substrate.
In recent years much attention has been devoted to the development of microelectronic circuit components. Piezoelectric materials in the form of deposited films have been used in microelectronic resonators, transducers, and other devices. These films are typically deposited on silicon substrates having doped p+ silicon membranes. However, p+ silicon membranes can be problematic during integration of the devices into active circuits.
Semi-insulating GaAs is useful as a substrate material in electronic devices. Its high electron mobility is advantageous in high speed transistors, integrated circuits, broad band amplifiers, and power field-effect transistors. However, a need exists for miniature passive resonators which can be incorporated into these active circuits. In particular, it would be desirable to be able to produce these resonators directly on a GaAs substrate which already supports other electronic components to facilitate circuit integration. It would further be desirable to be able to accomplish all the processing steps from a single side of the substrate.